Linux – Unable to run bash script on EC2 start-up

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I have scanned various resources and tried various things, but to no avail.

Here's the situation;

I have an EC2 instance which runs a node.js app. I also want to run a bash script (A loop with intermediate sleep) in the background which checks if there are any new changes to the git repository of the node app.

In the user-data part of my instance, I have this;

#!/bin/bash
su - ec2-user -c 'cd sample-node-app; node index.js'
su - ec2-user -c 'bash /home/ec2-user/check_git.sh &'

The script, adapted from here

#!/bin/bash
while true
do

#move into your git repo
cd ~/sample-node-app;

git fetch;
LOCAL=$(git rev-parse HEAD);
REMOTE=$(git rev-parse @{u});

#if our local revision id doesn't match the remote, we will need to pull the changes
if [ $LOCAL != $REMOTE ]; then
    #pull and merge changes
    git pull origin master;
    git reset --hard origin/master
    killall node

    npm start;
fi
sleep 5
done
  • Tried suggestions from here, here and adding the file path to rc.local. When I did the rc.local part, the node app terminated automatically on each start.
  • Have set permissions for the script using chmod +x check_git.sh.
  • Tried variations of user-data input like bash /home/ec2-user/check_git.sh and ./check_git.sh (I have #!/bin/bash at the top of the script.)

Thanks in advance.

Best Answer

Managed to get it working by adding the following in my EC2 user-data;

#cloud-config

runcmd:
 - rm -rf /var/lib/cloud/*
 - su - ec2-user -c 'bash check_git.sh'
 - su - ec2-user -c 'cd sample-node-app; node index.js'

Haven't found a reason as to why it works yet, but working on it.

EDIT

I managed to break the above for some reason. Worked at times, but not consistently. Eventually, I resorted to the following;

In check_git.sh, I have an if-statement to check and run the app:

if ! pgrep -x "node" > /dev/null
then
    node index.js &
fi

And the following in user-data of the EC2 instance:

#!/bin/bash
sudo rm -rf /var/lib/cloud/*
su - ec2-user -c 'bash /home/ec2-user/check_git.sh'
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